“…We have reported ( 34 ) that long-term memory of conflict favors the expression of fear memories, i.e., when tested 20 days after the conclusion of mixed-valence reinforcement, mice demonstrated an increase in the expression of fear when approaching the goal area (with its mixed-valence history of reinforcement). This increase in fear could reflect the impact of negativity biases on the expression of long-term memories ( 35 , 36 , 37 ).…”